What could be the estimated atomic mass of Silicon?
A. 26.2 amu
B. 28.1 amu
C. 29.8 amu
D. 30.1 amu

Answer:

2 NaI (aq) + Br2 (aq) → 2 NaBr (aq) + I2 (s)

This is an oxidation-reduction (redox) reaction:

2 Br0 + 2 e- → 2 Br-I

(reduction)

2 I-I - 2 e- → 2 I0

(oxidation)

Answer:

polymer mear least receptive to dye

,

Answer:

D

Explanation:

Silicon, element number 14 is the fourth element in the third period in the periodic table. Its electronic configuration is 1s^2 2s^2 2p^6 3s^2 3p^2.

The elemental symbol of the previous noble gas preceding the atom is replaced by the arrangement of the remaining electrons to form a noble gas configuration of an atom.

So for Silicon, we substitute [Ne] 1s^2 2s^2 2p^6 and the noble gas configuration can now be [Ne] 3s^2 3p^2.

Answer:

fossil fuels

Explanation:

Well I had some topics on this stuff last quarter in science and from what I can remember it should be fossil fuels I think that fossil fuels are technically renewable but they are considered non-renewable since they are either in small supplies, are hard to obtain or take a long time to form.

Answer:

2 N2O(g) + 3 O2(g) --> 4 NO2(g)

Explanation:

this is the chemical reaction balanced, if that was ur question.

Answer:

1. 80.9 g of CH₃OH

2. CO

3. 5.14moles

Explanation:

The reaction is:

CO  +  2H₂  →  CH₃OH

First place, we determine the moles of each reactant.

70.8 g . 1mol/ 28g = 2.53 moles of CO

20.4 g . 1mol / 2g = 10.2 moles of H₂

There is too much hydrogen, so the limiting reactant might be the carbon monoxide.

2 moles of H₂ react to 1 mol of CO

Then, 10.2 moles of H₂ may react to (10.2 . 1) /2 = 5.1 moles

We don't have enough CO, so it's ok that CO is the limiting. (We have 2.53 moles, we need 5.1 moles)

In the other hand, hydrogen is the excess reactant.

1 mol of CO react to 2 moles of hydrogen

2.53 moles may react to (2.53 . 2) /1  =5.06 moles

We have 10.2 moles, and we need 5.06 moles. Then (10.2 - 5.06) = 5.14 moles remains after the reaction goes complete.

Now that we know the limiting reactant, we can determine the grams of produced methanol. Ratio is 1:1

1 mol of CO produces 1 mol of CH₃OH

2.53 moles of CO must produce 2.53 moles of CH₃OH

We convert moles to mass: 2.53 mol . 32 g/mol = 80.9 g

Answer: The given demonstration does not support Boyle's Law.

Explanation:

According to Boyle's law, at constant temperature the pressure of an ideal gas is inversely proportional to the volume of gas.

[tex]P \propto \frac{1}{V}[/tex]

Therefore, an increase in volume of gas will lead to a decrease in pressure and vice-versa.

Now, according to the given data of volumes there is occurring an increase on moving from final volume 1 to final volume 3. This means that pressure is decreasing.

As a result, if a balloon was squeezed or compressed then it would get smaller. But in the given demonstration pressure is not given.

Thus, we can conclude that the given demonstration does not support Boyle's Law.

Answer:

5.1044844 x 10^7/cm^3 = 5E7

Explanation:

The atomic weight and density (at 25 ° C) for copper are 63.5 g/mol or 0.0635 kg/mol and 8,960 kg/m^3

First lets find the value of N, number of atomic sites per cubic meter for copper, from its atomic weight Acu, its density, and Avogadro’s number NA

N = NA x ρ / Acu = 6.023 x 10^23 x 8,960 kg/m^3 / 0.0635 kg/mol = 8.4985953 x 10^28 atoms / m3

Temperature dependency can be given as :

Arrhenius equation

Nv = N e^(-EA/KT)

N = no. of atoms initially

Ev = activation energy

Nv = 8.4985953 x 10^28 atoms / m^3 exp^-(0.9ev/atom /8.617x10-5 eV/(atom-K) x 298 K

Nv = 5.1044844 x 10^13 /m3

vacancies per cm^3 = 5.1044844 x 10^7/cm^3 = 5E7

The molecular weight of [tex](NH_4)_2SO_4[/tex] would be 132 g/mol.

The molecular weight, otherwise known as the molar mass of substances is the sum of the molar weights of individual atoms that make up the substance.

[tex](NH_4)_2SO_4[/tex] is made up of 2 atoms of N, 8 atoms of H, 1 atom of S, and 4 atoms of O.

Thus, the molecular weight of [tex](NH_4)_2SO_4[/tex] = (14x2) + (1x8) + 32 + (16x4)

                                                                     = 132 g/mol

In other words, the molecular weight of [tex](NH_4)_2SO_4[/tex] is 132 g/mol.

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Answer:

wings

Explanation:

this is an example of movement because it allows birds to fly in the air

Answer:

2.4.17892

Explanation:

34.1/816×100=4.17892

Answer:

develops,blossoms are synonyms

The mass of phosphorus in a 63 kg person would be 0.63 kg or 630 grams.

According to several research findings, the percentage of phosphorus in the human body is about 1%. This means that the weight of an average human is about 1% phosphorus.

Using the above information, the mass of phosphorus in a 63 kg person can be estimated as follows:

1/100 x 63 = 0.63 kg

Since 1 kg = 1000 grams

Thus, 0.63 kg = 0.63 x 1000

                       = 630 grams

In other words, the mass of phosphorus in a 63 kg person would be 0.63 kg or 630 grams.

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Answer:

2K +F₂→ 2KF

Explanation:

When we balance an equation, we are trying to ensure that the number of atoms of each element is the same on both sides of the arrow.

On the left side of the arrow, there is 1 K atom and 2 F atoms. On the right, there is 1 K and 1 F atom.

Since the number of K atoms is currently balanced, balance the number of F atoms.

K +F₂→ 2KF

Now, that the number of F atoms is balanced on both sides, check if the number of K atoms are balanced.

Left

K atoms: 1

F atoms: 2

Right

K atoms: 2

F atoms: 2

The number of K atoms is not balanced.

2K +F₂→ 2KF

Left

K atoms: 2

F atoms: 2

Right

K atoms: 2

F atoms: 2

The equation is now balanced.

sorry needed the points

Answer: A 2.1

Explanation:

Polyatomic ions are ions made up of more than one atom.

What are Atoms?

Atoms are the smallest particles of matter that make up all objects. They are composed of protons, neutrons, and electrons. Protons and neutrons make up the nucleus of the atom, while electrons orbit around the nucleus. Atoms are the basic units of matter and are the building blocks of all living and nonliving things.

Polyatomic ions are ions that consist of two or more atoms covalently bonded together and carrying a net electric charge. Examples of polyatomic ions include nitrate (NO3−), sulfate (SO42−), phosphate (PO43−), and carbonate (CO32−).

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3.2 g KClO3

Explanation:

1.1 g C12H22O11 × (1 mol C12H22O11/342.3 g C12H22O11)

= 0.0032 mol C12H22O11

0.0032 mol C12H22O11 × (8 mol KClO3/1 mol C12H22O11)

= 0.026 mol KClO3

Therefore, the minimum amount of KClO3 needed is

0.026 mol KClO3 × (122.55 g KClO3/1 mol KClO3)

= 3.2 g KClO3

Answer:

.

Explanation:

a. 2, 2

b. 2, 2

c. 2, 3, 2

d. 1, 5, 3, 4

Just make sure there is an equal amount of each ELEMENT on each side of the reaction. Starting with, O, H, C, then other elements is a good method too

They are distinct Similarity: Compared to crustal rocks, mantle rocks have higher concentrations of magnesium and iron. The deep mantle's rocks are under extreme pressure and heat.

Earth's interior is made up primarily of the mantle, which is solid. Between the thin crust at the surface of the planet and its dense, extremely hot core is the mantle. A staggering 84% of the volume of the Earth is made up of the mantle, which is around 2,900 kilometers 1,802 miles thick.

The thickest layer on Earth measures just under 3,000 kilometers 1,865 miles. The beginning is only 18.6 miles 30 kilometers below the surface. It is thick, heated, and semi-solid like caramel candy, mostly made of iron, magnesium, and silicon. It circulates, much like the layer beneath it.

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The allowed concentration of Cl in water is 250 ppm. Then the equivalent concentration in molarity is 0.007 molar.

Molarity is a common term used to express the concentration of a solution. It is the ratio of the number of moles of solute to the volume of solution in liters. Molarity is a temperature dependent measurement.

Parts per million is another term of concentration have the formula as written below:

ppm = ws/W × 10⁶

Where, ws is the weight of solute and W be the weight of solution in grams.

1 molar = 35500 ppm

therefore, 250 ppm = 250 ppm × 1M /35500 ppm  = 0.007 M.

Hence, the molarity of the salt solution will with the maximum  allowed concentration will be 0.007 M.

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The complete question is: [tex]CH_{4}(g) + O_{2}(g) \rightarrow CO_{2}(g) + H_{2}O(g)[/tex] balance?

Answer:  [tex]CH_{4}(g) + 2O_{2}(g) \rightarrow CO_{2}(g) + 2H_{2}O(g)[/tex] is a balanced equation.

Explanation:

A chemical equation which contains same number of atoms on both reactant and product side is called a balanced chemical equation.

For example, [tex]CH_{4}(g) + O_{2}(g) \rightarrow CO_{2}(g) + H_{2}O(g)[/tex]

Here, number of atoms on reactant side are as follows.

Number of atoms on product side are as follows.

To balance this equation multiply [tex]O_{2}[/tex] by 2 on reactant side and multiply [tex]H_{2}O[/tex] by 2 on product side. Hence, the equation can be re-written as follows.

[tex]CH_{4}(g) + 2O_{2} \rightleftharpoons CO_{2}(g) + 2H_{2}O(g)[/tex]

Here, number of atoms on reactant side are as follows.

Number of atoms on product side are as follows.

Since, there are same number of atoms on both reactant and product side. So, this equation is a balanced equation.

Thus, we can conclude that [tex]CH_{4}(g) + 2O_{2}(g) \rightarrow CO_{2}(g) + 2H_{2}O(g)[/tex] is a balanced equation.

Answer:

Option 2

Explanation:

Answer:

Packed inside the nucleus of every human cell are nearly 6 feet of DNA, which is divided into 46 individual molecules, one for each chromosome and each about 1.5 inches long. Packing all this material into a microscopic cell nucleus is an extraordinary feat of packaging.

Explanation:

Packed inside the nucleus of every human cell are nearly 6 feet of DNA, which is divided into 46 individual molecules, one for each chromosome and each about 1.5 inches long. Packing all this material into a microscopic cell nucleus is an extraordinary feat of packaging. For DNA to function, it can't be crammed into the nucleus like a ball of string. Instead, it is combined with proteins and organized into a precise, compact structure, a dense string-like fiber called chromatin.

(hope this helps can i plz have brainlist :D hehe)

In order to react with 467.08 grams of O2, 4034.95 g of toluene (C6H5CH3) is required.

Toluene is a white liquid hydrocarbon found in petroleum and coal tar that is employed like a solvent and in the synthesis of organic compounds. Toluene is a naturally occurring substance found in crude oil and is used for oil refining as well as the production of glues, lacquers, paints, and explosives. Toluene can be discovered in household products like paint, paintbrush cleaner, nail polish, glue, inks, and stain removers.

For the balanced equation

2C6H5CH3 + 3O2 → 7CO2 + 4H2O

We required three steps

1.) Convert mass of O2 to mol of O2

mole = mass / molar mass

2.) Find mole of C6H5CH3 by multiply mol O2 by the mol ratio between O2 and C6H5CH3 in balanced equation.

3.) Find mass C6H5CH3 by multiply mol C6H5CH3 by its molar mass (92.14 g/mol)

= 467.08 gm /15.999 gm × 3/ 2 ×92.14 gm

= 4034.95 gm. of C6H5CH3

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Answer:

Just use a text book.. So that you get the concept

Hence, [tex]C_{20}H_{20}O_4[/tex] is the molecular formula of a compound's empirical formula is [tex]C_5H_5O[/tex].

The empirical formula is the chemical formula of a compound that gives the proportions (ratios) of the elements present in the compound but not the actual numbers or arrangement of atoms.

Divide the molar mass of the compound by the empirical formula mass. The result should be a whole number or very close to a whole number. Multiply all the subscripts in the empirical formula by the whole number

The molar mass of the empirical formula compound [tex]C_5H_5O[/tex] is 46.06844 g/mol.

The molecular mass of the compound is 162.2g given.

162.2g ÷ 46.06844

3.520848546 =4

[tex]C_{20}H_{20}O_4[/tex] is the molecular formula.

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The number of moles of the ideal gas is 0.12 moles. Option A

In the context of the problem that we have here, we are looking at the ideal  gas equation. When we look at the idea gas equation, we can tell that we would have the pressure of the gas, the volume of the gas as well as the temperature of the gas in view as is the case that we have here.

Thus, the idea that we are asked to pass across in the question is that we should be able to find out the number of moles that we have in the compound that have the variables that have been listed here.

Pressure (P) =  1 atm

Volume (V) = 1 L

Temperature (T) = 1 K

Number of moles (n) = ?

Using;

PV = nRT

n = PV/RT

n = 1 * 1/0.082 * 1

n = 0.12 moles

The moles of the gas is 0.12 moles.

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Answer:

C₂ = 50 mg/L

C₃ = 42.5 mg/L

Explanation:

To do this, we just need to use the following expression:

C₁V₁ = C₂V₂     (1)

Where:

C₁: Original concentration of the Iron solution (mg/L)

V₁: aliquot of the iron solution (mL or L)

C₂: Concentration of the iron after beind dilluted (mg/L)

V₂: Volume of the flask that's being used.

Using the above expression, we just solve for C₂:

C₂ = C₁V₁ / V₂   (2)

We have the required volumes, but we do not have the concentration of the iron solution (C₁). To determine this, we use the initial flask of 100 mL and the mass of the iron:

C₁ = 25 mg / 0.1 L = 250 mg/L

With this value, we can replace in (2) to get the concentration on each flask.

Flask 1:

We have an aliquot of 20 mL, and it was dilluted to 100 mL, the concentration would be:

C₂ = 250 mg/L * (20/100)

Flask 2:

We have an aliquot of 17 mL dilluted to 100 mL so:

C₃ = 250 * (17/100)

Hope this helps

The concentration of iron in mg/L in each of the two flasks is 50 mg/l and 42.5 mg/L respectively.

The initial concentration of iron in the sample is obtained as follows:

A vitamin tablet containing 25 mg of iron is dissolved in 6M HCl and then made up to 100 mL in a 100 mL volumetric flask with DI water.

Concentration of iron in the solution = 25 mg/ 100 mL

Converting to mg/L; 1 L = 1000 mL, then 100 mL = 1000 * 1 L/ 1000 mL = 0.1 L

Concentration of iron in the solution in mg/L = 25 mg / 0.1 L = 250 mg/L

Then 20 mL and 17 mL of this solution were pipetted into separate 100 mL volumetric flasks and each of these was brought up to 100 mL volume by diluting with DI water to the mark.

Using the dilution formula C₁V₁ = C₂V₂ to determine the concentration of iron in each of these flasks:

C₁ = initial concentration; V₁ = initial volume

C₂ = final concentration; V₂ = final volume

Flask 1:

C₁ = 250 mg/L, V₁ = 20 mL, C₂ = ?, V₂ = 100 mL

C₂ = C₁V₁ / V₂

C₂ = 250 * 20 / 100

C₂ = 50 mg/L

Flask 2:

C₁ = 250 mg/L, V₁ = 17 mL, C₂ = ?, V₂ = 100 mL

C₂ = C₁V₁ / V₂

C₂ = 250 * 17 / 100

C₂ = 42.5 mg/L

Therefore, the concentration of iron in mg/L in each of the two flasks is 50 mg/l and 42.5 mg/L respectively.

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Answer:

this is a animal cell..I hope you received this on time

Answer:

building amino acids in proteins

Explanation: